This invention relates to the field of automated palletizing of cased goods.
In an automated palletizing machine, called palletizers in the trade, cases of goods are received from a production line on an infeed conveyor. The cases of goods can be, for example, aluminum cans filled with beverages and wrapped in cardboard boxes, plastic water bottles shrink-wrapped together, or any other case or bundle. The cases of goods can be any product packaged in a similar manner or shape as these examples that is ready to be further packaged on a pallet. The palletizer groups the cases in layers, then successive layers are stacked on top of one another to form a load. The load of cases in turn can be stacked on top of a base, such as a pallet, that facilitates movement of the load by machine, such as by a forklift. The palletizer arranges the cases into layers and stacks them at a rapid pace—a pace equaling the speed at which the cases are received from the infeed conveyor.
For stability, the layers of cases can be arranged into a pattern. The patterns of adjacent layers may be alternated so that the load of cases is well supported, secure, and balanced. In order to arrange the cases in a layer into a desired pattern appropriate for stacking on top of the previous layer, it may be necessary to turn some of the cases as the layer is formed so that certain cases have a different orientation relative to the layer than others.
During the process of case turning, the cases can be damaged. Typically a prior art turning device comes into contact with a portion of the case while the case is traveling forward in a direction of case travel on the conveyor system of the palletizer. The turning device pushes on one end of the case and temporarily slows the forward movement of the one end of the case while the other end of the case continues to move forward at a greater speed than the one end. The difference in the forward speed of each end of the case causes the case to rotate. The contact of the turning device with the cases during case turning can generate significant forces when the cases are traveling at high speeds. As a result, the packaging of the case, or even the product itself, can be damaged during case turning. Also, case turning can cause the palletizer to operate unreliably. The case turning can cause the packaging of the case to come loose and jam the machinery of the palletizer. The case turning machinery itself can wear more quickly than other components of the palletizer because of its harsh contact with the cases. As a result of its more rapid wear, the case turning machinery can necessitate more frequent maintenance and down time of the palletizer. In addition, to operate effectively the case turning procedure can require the palletizer to operate at a lower case per minute speed than it might otherwise operate if the case turning did not occur.
Thus, benefit can be had from case turning that operates reliably and quickly, while causing less damage to the cases, so that losses from damaged cases can be minimized and so that the palletizer can be run at a more rapid pace and more reliably.